The 39-year-old actor appeared on The Howard Stern Show — and revealed there is a very good reason he wasn't attracted to his now wife when they first met nearly two decades ago at 19 and 14 years old, respectively.

"I think I was her first kiss, like, on the show," he said before adding that he would help her with her chemistry homework. "It was really weird. I was like, 'Isn't this illegal?' It was really awkward. She was 14! She was like my little sister. I wanted to make sure she was OK."

Despite the age gap, Mila and Ashton's relationship timeline sounds like it's straight out of a movie.

The two stars, who are parents to two adorable kids,Wyatt and Dimitri, might have married in 2015, but they met on the set of The 70s Show in 1998. That's right, the couple stayed friends for seven years through relationships, divorces, and all the other drama that comes along with Hollywood.

"We started dating with the idea we're both never going to get married," Mila confessed. "[Ashton] just got out of a marriage. I got out of a long relationship. I was single and having the best time ever. I was totally dating, having a great time, and I was like, 'I'm never getting married.' He's like, 'Great, neither am I!' And we're like shaking hands on it and we're like, 'Life is great!' A year later, we're like, 'Tomorrow, let's get married.'"

Well, the couple was clearly meant to be because Mila went on to explain how she developed serious feelings for her hubby. "It ended up being just having fun to genuinely wanting [more] —when I realized I was nervous [about him going out with someone else and me losing him], was when I spoke to him. I was like, I don't like this anymore."

And the rest is history!

Click through the gallery below to see Mila and Ashton's complete relationship timeline.

2001

The actors' characters were love interests on the show, and to make matters even more interesting, Ashton was Mila's first kiss. In 2001, she opened up about what it was like locking lips with the hot actor.

"I was like, 'Oh, he's so cute; it's the Calvin Klein model!' Then I was like, 'I have to kiss him?' I was so nervous and uncomfortable," she admitted. "I had the biggest crush on him."

2012

Mila and Ashton began sparking dating rumors in 2012, but were adamant about keeping the relationship private.

"You know, I've learned the hard way how valuable privacy is," Ashton said. "And I've learned that there are a lot of things in your life that really benefit from being private. And relationships are one of them. And I am going to do everything in my power to have this relationship be private."

2014

By 2014, it was confirmed the couple was a pair when Mila was spotted wearing an engagement ring at a Los Angeles Lakers game. Later that year, she gave birth to their first child, Wyatt Isabelle Kutcher.